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BulletSim: organize MoveLinear code for understandability. Make LIMIT_MOTOR_UP contribution a velocity and not a force.

connector_plugin^2
Robert Adams 2012-11-25 19:06:53 -08:00
parent f977131fe0
commit 4c077a0694
1 changed files with 40 additions and 89 deletions
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129
OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs
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@ -84,7 +84,6 @@ namespace OpenSim.Region.Physics.BulletSPlugin
private Vector3 m_linearMotorDirection = Vector3.Zero; // velocity requested by LSL, decayed by time
private Vector3 m_linearMotorOffset = Vector3.Zero; // the point of force can be offset from the center
private Vector3 m_linearMotorDirectionLASTSET = Vector3.Zero; // velocity requested by LSL
private Vector3 m_newVelocity = Vector3.Zero; // velocity computed to be applied to body
private Vector3 m_linearFrictionTimescale = Vector3.Zero;
private float m_linearMotorDecayTimescale = 0;
private float m_linearMotorTimescale = 0;
@ -577,15 +576,6 @@ namespace OpenSim.Region.Physics.BulletSPlugin
{
if (!IsActive) return;
// DEBUG
// Because Bullet does apply forces to the vehicle, our last computed
// linear and angular velocities are not what is happening now.
// Vector3 externalAngularVelocity = Prim.ForceRotationalVelocity - m_lastAngularVelocity;
// m_lastAngularVelocity += (externalAngularVelocity * 0.5f) * pTimestep;
// m_lastAngularVelocity = Prim.ForceRotationalVelocity; // DEBUG: account for what Bullet did last time
// m_lastLinearVelocityVector = Prim.ForceVelocity * Quaternion.Inverse(Prim.ForceOrientation); // DEBUG:
// END DEBUG
MoveLinear(pTimestep);
// Commented out for debug
MoveAngular(pTimestep);
@ -612,67 +602,22 @@ namespace OpenSim.Region.Physics.BulletSPlugin
// Also does hover and float.
private void MoveLinear(float pTimestep)
{
/*
// m_linearMotorDirection is the target direction we are moving relative to the vehicle coordinates
// m_lastLinearVelocityVector is the current speed we are moving in that direction
if (m_linearMotorDirection.LengthSquared() > 0.001f)
{
Vector3 origDir = m_linearMotorDirection; // DEBUG
Vector3 origVel = m_lastLinearVelocityVector; // DEBUG
// DEBUG: the vehicle velocity rotated to be relative to vehicle coordinates for comparison
Vector3 vehicleVelocity = Prim.ForceVelocity * Quaternion.Inverse(Prim.ForceOrientation); // DEBUG
// Add (desiredVelocity - lastAppliedVelocity) / howLongItShouldTakeToComplete
Vector3 addAmount = (m_linearMotorDirection - m_lastLinearVelocityVector)/(m_linearMotorTimescale) * pTimestep;
m_lastLinearVelocityVector += addAmount;
float decayFactor = (1.0f / m_linearMotorDecayTimescale) * pTimestep;
m_linearMotorDirection *= (1f - decayFactor);
// Rotate new object velocity from vehicle relative to world coordinates
m_newVelocity = m_lastLinearVelocityVector * Prim.ForceOrientation;
// Apply friction for next time
Vector3 frictionFactor = (Vector3.One / m_linearFrictionTimescale) * pTimestep;
m_lastLinearVelocityVector *= (Vector3.One - frictionFactor);
VDetailLog("{0},MoveLinear,nonZero,origlmDir={1},origlvVel={2},vehVel={3},add={4},decay={5},frict={6},lmDir={7},lvVec={8},newVel={9}",
Prim.LocalID, origDir, origVel, vehicleVelocity, addAmount, decayFactor, frictionFactor,
m_linearMotorDirection, m_lastLinearVelocityVector, m_newVelocity);
}
else
{
// if what remains of direction is very small, zero it.
m_linearMotorDirection = Vector3.Zero;
m_lastLinearVelocityVector = Vector3.Zero;
m_newVelocity = Vector3.Zero;
VDetailLog("{0},MoveLinear,zeroed", Prim.LocalID);
}
*/
m_newVelocity = m_linearMotor.Step(pTimestep);
Vector3 linearMotorContribution = m_linearMotor.Step(pTimestep);
// Rotate new object velocity from vehicle relative to world coordinates
m_newVelocity *= Prim.ForceOrientation;
// m_newVelocity is velocity computed from linear motor in world coordinates
linearMotorContribution *= Prim.ForceOrientation;
// ==================================================================
// Gravity and Buoyancy
// There is some gravity, make a gravity force vector that is applied after object velocity.
// m_VehicleBuoyancy: -1=2g; 0=1g; 1=0g;
Vector3 grav = Prim.PhysicsScene.DefaultGravity * (1f - m_VehicleBuoyancy);
/*
* RA: Not sure why one would do this unless we are hoping external forces are doing gravity, ...
// Preserve the current Z velocity
Vector3 vel_now = m_prim.Velocity;
m_dir.Z = vel_now.Z; // Preserve the accumulated falling velocity
*/
// Current vehicle position
Vector3 pos = Prim.ForcePosition;
// Vector3 accel = new Vector3(-(m_dir.X - m_lastLinearVelocityVector.X / 0.1f), -(m_dir.Y - m_lastLinearVelocityVector.Y / 0.1f), m_dir.Z - m_lastLinearVelocityVector.Z / 0.1f);
// ==================================================================
Vector3 terrainHeightContribution = Vector3.Zero;
// If below the terrain, move us above the ground a little.
float terrainHeight = Prim.PhysicsScene.TerrainManager.GetTerrainHeightAtXYZ(pos);
// Taking the rotated size doesn't work here because m_prim.Size is the size of the root prim and not the linkset.
@ -687,6 +632,8 @@ namespace OpenSim.Region.Physics.BulletSPlugin
VDetailLog("{0},MoveLinear,terrainHeight,terrainHeight={1},pos={2}", Prim.LocalID, terrainHeight, pos);
}
// ==================================================================
Vector3 hoverContribution = Vector3.Zero;
// Check if hovering
// m_VhoverEfficiency: 0=bouncy, 1=totally damped
// m_VhoverTimescale: time to achieve height
@ -726,24 +673,22 @@ namespace OpenSim.Region.Physics.BulletSPlugin
// RA: where does the 50 come from?
float verticalCorrectionVelocity = pTimestep * ((verticalError * 50.0f) / m_VhoverTimescale);
// Replace Vertical speed with correction figure if significant
if (Math.Abs(verticalError) > 0.01f)
if (verticalError > 0.01f)
{
m_newVelocity.Z += verticalCorrectionVelocity;
hoverContribution = new Vector3(0f, 0f, verticalCorrectionVelocity);
//KF: m_VhoverEfficiency is not yet implemented
}
else if (verticalError < -0.01)
{
m_newVelocity.Z -= verticalCorrectionVelocity;
}
else
{
m_newVelocity.Z = 0f;
hoverContribution = new Vector3(0f, 0f, -verticalCorrectionVelocity);
}
}
VDetailLog("{0},MoveLinear,hover,pos={1},dir={2},height={3},target={4}", Prim.LocalID, pos, m_newVelocity, m_VhoverHeight, m_VhoverTargetHeight);
VDetailLog("{0},MoveLinear,hover,pos={1},dir={2},height={3},target={4}",
Prim.LocalID, pos, hoverContribution, m_VhoverHeight, m_VhoverTargetHeight);
}
// ==================================================================
Vector3 posChange = pos - m_lastPositionVector;
if (m_BlockingEndPoint != Vector3.Zero)
{
@ -781,60 +726,66 @@ namespace OpenSim.Region.Physics.BulletSPlugin
}
}
#region downForce
Vector3 downForce = Vector3.Zero;
// ==================================================================
Vector3 limitMotorUpContribution = Vector3.Zero;
if ((m_flags & (VehicleFlag.LIMIT_MOTOR_UP)) != 0)
{
// If the vehicle is motoring into the sky, get it going back down.
// Is this an angular force or both linear and angular??
float distanceAboveGround = pos.Z - terrainHeight;
if (distanceAboveGround > 2f)
if (distanceAboveGround > 1f)
{
// downForce = new Vector3(0, 0, (-distanceAboveGround / m_bankingTimescale) * pTimestep);
// downForce = new Vector3(0, 0, -distanceAboveGround / m_bankingTimescale);
downForce = new Vector3(0, 0, -distanceAboveGround);
limitMotorUpContribution = new Vector3(0, 0, -distanceAboveGround);
}
// TODO: this calculation is all wrong. From the description at
// (http://wiki.secondlife.com/wiki/Category:LSL_Vehicle), the downForce
// has a decay factor. This says this force should
// be computed with a motor.
VDetailLog("{0},MoveLinear,limitMotorUp,distAbove={1},downForce={2}",
Prim.LocalID, distanceAboveGround, downForce);
Prim.LocalID, distanceAboveGround, limitMotorUpContribution);
}
#endregion // downForce
// ==================================================================
Vector3 newVelocity = linearMotorContribution
+ terrainHeightContribution
+ hoverContribution
+ limitMotorUpContribution;
// If not changing some axis, reduce out velocity
if ((m_flags & (VehicleFlag.NO_X)) != 0)
m_newVelocity.X = 0;
newVelocity.X = 0;
if ((m_flags & (VehicleFlag.NO_Y)) != 0)
m_newVelocity.Y = 0;
newVelocity.Y = 0;
if ((m_flags & (VehicleFlag.NO_Z)) != 0)
m_newVelocity.Z = 0;
newVelocity.Z = 0;
// ==================================================================
// Clamp REALLY high or low velocities
float newVelocityLengthSq = m_newVelocity.LengthSquared();
float newVelocityLengthSq = newVelocity.LengthSquared();
if (newVelocityLengthSq > 1e6f)
{
m_newVelocity /= m_newVelocity.Length();
m_newVelocity *= 1000f;
newVelocity /= newVelocity.Length();
newVelocity *= 1000f;
}
else if (newVelocityLengthSq < 1e-6f)
m_newVelocity = Vector3.Zero;
newVelocity = Vector3.Zero;
// ==================================================================
// Stuff new linear velocity into the vehicle
Prim.ForceVelocity = m_newVelocity;
Prim.ForceVelocity = newVelocity;
// Prim.ApplyForceImpulse((m_newVelocity - Prim.Velocity) * m_vehicleMass, false); // DEBUG DEBUG
Vector3 totalDownForce = downForce + grav;
// Other linear forces are applied as forces.
Vector3 totalDownForce = grav * m_vehicleMass;
if (totalDownForce != Vector3.Zero)
{
Prim.AddForce(totalDownForce * m_vehicleMass, false);
// Prim.ApplyForceImpulse(totalDownForce * m_vehicleMass, false);
Prim.AddForce(totalDownForce, false);
}
VDetailLog("{0},MoveLinear,done,lmDir={1},lmVel={2},newVel={3},primVel={4},totalDown={5}",
Prim.LocalID, m_linearMotorDirection, m_lastLinearVelocityVector, m_newVelocity, Prim.Velocity, totalDownForce);
Prim.LocalID, m_linearMotorDirection, m_lastLinearVelocityVector,
newVelocity, Prim.Velocity, totalDownForce);
} // end MoveLinear()